That missing linux/autoconf.h looks suspicious. Does /usr/src/linux-headers-2.6.38-2-686-bigmem/include/linux/autoconf.h exist? If it doesn't, your kernel headers are incomplete. If it does, there's a bug in a makefile somewhere that causes it not to look in the right directories.
–
GillesApr 9 '11 at 13:38

It's instead found in /usr/src/linux-headers-2.6.38-2-686-bigmem/include/generated/autoconf.h. This is in comparison to 2.6.32's /usr/src/linux-headers-2.6.32-5-686-bigmem/include/linux/autoconf.h.
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TshepangApr 9 '11 at 14:08